Zeaxanthin ('03, '06, '10, 2011) and macular degeneration
A 2011 study confirms that vision is improved in the elderly with early macular degeneration by adding Zeaxanthin as a nutritional supplement. Zeaxanthin is a a carotenoid.
The Zeaxanthin and Visual Function Study demonstrates that dietary Zeaxanthin improved vision, including improvement in night blindness and seeing fine detail.
The one year study involved elderly veterans who were given 8mg of Zeaxanthin daily. The researcher found improvement in the ability to drive at night, and an average improvement of 1.5 lines or 8.5 letters on an eye chart, and the disappearance of blind spots.
Some of the people were additionally given 9 mg of lutein daily.
Zeaxanthin and lutein are two carotenoids (part of a family of antioxidants that give fruits and vegetables their color) found in the retina and macula of the eye. Zeaxanthin protects the cones, or photoreceptors responsible for central vision, color perception, and fine detail.
Since the average daily diet in the U.S. does not include enough fresh fruits and vegetables, it is difficult, particularly for the elderly, to maintain healthy macular pigment levels to protect their vision.
Researchers: Stuart Richer, PhD, OD, et al
Published: Randomized, double-blind, placebo-controlled study of zeaxanthin and visual function in patients with atrophic age-related macular degeneration: the Zeaxanthin and Visual Function Study (ZVF) FDA IND #78, 973, Optometry, November, 2011
An earlier study also found that zeaxanthin supplementation can increase the density of pigments in the macula pigment. The increased density helps protect the macula from the damage caused by blue light and sunlight.
Reference: The Zeaxanthin and Visual Function Study in Atrophic Age Related Macular Degeneration (ZVF-FDA IND #78,973) - MP and Foveal Shape Discrimination: S.P. Richer1, et al.
One of the early studies on the effect of zeaxanthin levels in the blood and incidence of AMD found a very strong inverse association. Patients with high levels of zeaxanthin in their blood plasma had a 93% reduced risk of developing AMD compared to patients with low zeaxanthin levels. Further, the researchers reported that, globally, patients with high levels of lutein and zeaxanthin had a 79% reduced risk.
Previous research had investigated the benefits of lutein and zeaxanthin combined -- this study focused on zeaxanthin alone.
They also found a strong inverse relationship between nuclear cataract (only that type of cataract) and zeaxanthin levels. Those with high levels of zeaxanthin had a 75% lower chance of developing nuclear cataracts. In contrast, lutein levels were not associated with cataract risk.
The scientists pointed out that the rationale for the important role of zeaxanthin lies in the fact that in healthy eyes the proportion of zeaxanthin compared to lutein is much greater in the center of the retina - the macula. They also found that while both lutein and zeaxanthin protect against oxidative stress from UV light exposure, zeaxanthin appears to be a better protector.
Researchers: C. Delcourt, I. Carriere, et al,
Published: Plasma Lutein and Zeaxanthin and Other Carotenoids as Modifiable Risk factors for Age Related Maculopathy and Cataract: the POLA study, IOVS, June 2006.
In another study scientists reported that patients with high blood plasma levels of zeaxanthin had a 50% reduced risk of developing macular degeneration compared to subjects with low levels. These findings were even more striking for the top 1/5th of the group whose natural Mediterranean diet provided them with higher levels of the nutrients daily. These findings were correct after adjusting for risk factors such as age and genetics.
Researchers: C. Gale, N, F. Hall, et al,
Published: Lutein and zeaxanthin status and risk of age-related macular degeneration, Investigative Ophtalmology and Visual Science, June, 2003.